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Topic: Ether and loss of prime (Read 12699 times)

New guy here. Kerry Pinkerton from Huntsville, AL. Recently purchased a Fleetwood Discovery with the 3126 diesel. My cousin was down helping me do some TLC and we decided to change the fuel/water separator filter (only one filter on this engine). No prime pump.

The CAT manual that came in the coach said not to fill the new filter with diesel. The WIX box says the same thing. WRONG! Ran for a couple minutes and died would not restart.

Called the CAT folks and they said I would probably have to call someone in but I could try and fill the filter and get up in the engine bay (right side) and loosen the fuel line and crank until fuel ran out. Also called Freightliner, they said the same thing but to do it at the fuel filter because the pump was nearly impossible to get to. Did that, crank crank crank ( in 30 second intervals with a good wait between). Starting to get nervous.

Called a mechanic that has done some work for me and works on various diesel trucks and tractors. Described the problem and he said, spray some starting fluid in the inlet, it will start and then pick up the fuel. We did exactly that and it fired right up. I noticed the CAT book said all sorts of safety warnings about Ether but not how to use it. It didn't take much or log and the motor runs great. Big sigh of relief.

Now I see all the warnings from Brent about the intake heaters and ether which I respect. Does anyone know how to disconnect the intake heater if this should happen again? It would be nice if it was on a breaker of switch...

So what is the proper way not to have this happen again? Ignore the Cat and WIX warning not to prefill the new filter with fuel?

Actually, the better idea is to properly change the filter FOR THE WAY YOUR FUEL SYSTEM IS SET UP. The engine manufacturer does not spec or fit the fuel filter/filters. They just give the micron rating to which it must be filtered.

Freightliner chose (poorly IMO) to use a single filter and no primer pump on many of their chassis. Your Caterpillar owners manual is correct, but only for a "proper" fuel system with manual primer pump.

So, for you single filter, no primer pump application, here is what you need to do:

Pre-fill the filter. The smaller outer holes are the inlet. Fill them, not the large center hole.

Insure that the level of fuel in the tank is at or above the level of the filter housing. If the level if fuel in the tank is lower, fuel will drain out of the line and leave you with 30'+ of AIR in the line. Better yet, install a diesel compatible ball valve on the inlet to the fuel filter and turn it off while changing filters.

Yes, you can disconnect power to the intake manifold heater-- access is on the top of the engine, but ether is not needed if you properly change the filter.

It's unfortunate that the documentation is misleading. A lot of owners don't do the internet and only rely on their manuals. Now I know.

I was just told by the old mechanic that suggested the ether that the intake heater only comes on in cold weather anyway. Do you agree with that? And will the use of ether in the event of running out of fuel cause problems if not overused? A small engine guy once told me to not use ether but rather carb cleaner to help start small engines. Would that be a better choice in an emergency?

Yes, the engine manuals are written for "all on-highway" applications of a particular engine. There will be long sections on the use of manual transmissions and other things that clearly do not apply to our motorhomes.

Because spraying any flammable/explosive gas onto a red hot heater grid can cause an explosion, I would not recommend doing that. Better to properly bleed the air out of the system.

Sadly, in some cases, that means opening the filter or bleed screw and pressurizing the fuel tank (1-2 PSI-- just enough to force fuel from the tank to the filter). Takes two people and is a pain. But a lesson learned after messing up just once.

May I add something to reinforce Brett's thoughts. Any time ether is sprayed into a engine with aManifold Intake Heater , bad things will happen real bad. What will happen the ether will settle orstay in bottom of charged air cooler. Cranking engine the intake heater will light the ether ( boom )engine will go to its highest top rpm's known to mankind. Called a engine runway, if things settleDown before engine stops now comes the damage, stretched head bolts, bent push rods, bent valves,Just to name a few. Question about how can you go around system and disconnect intake heater,Again do not go there. Not understanding damage by random starting ether usage (broken rings inCold weather etc.) last to reinforce Brett Cat 2 micron fuel refill with fuel. You need to take a gallonof diesel fuel and take a paint strainer and filter diesel fuel into clean clear container than refill your2 micron fuel filter. If you take unfiltered diesel fuel and refill filter and start engine any dirt will go Direct to the injectors. Dave Atherton Retired Cat mechanic.

Kerry, you may also want to consider upgrading your secondary fuel filter housing by adding a manual prime pump. If you search this forum you will find several posts with the parts required. You can also change your primary filter base with one from racor which has an electric fuel pump to prime the system, it primes to 10 psi. However this is also a 400.00 dollar part.

Will agree with everyone, Ether and intake heaters are a bad combination.

They come on based on the sum of the air charge temperature and coolant temperature, it must be below a threshold liked 110 deg F. The turn on time will depend on that sum. I seem to remember something that the baro sensor my have a slight part in it as well but not for sure on that. Perhaps Dave or Brett can add to that.

I'm not a fan of pre filling filters because of the chance of getting dirt in, 2 microns is hard to see. However it is the least expensive as long as nothing gets in the outlet side.

Sadly, this is one of those Freightliner chassis with only a single (non-Caterpillar) fuel filter. So, can not add the Caterpillar manual pump which bolts up to the Caterpillar secondary fuel filter housing.

Being one of those folks with the Freightliner chassis that only has the single fuel/water separator, I'm a bit concerned that FL cheaping out might leave me on the side of the road someday. I researched the WIX 33783 filter I used and discovered it is a 2 micron filter. Would it make sense to add a 30 micron filter immediately preceding the 2 micron or just get a few of the 2 microns and expect to change them as needed?

Pinkertonk, we answered post yesterday and kinda confused. Why are you changing the fuelsystem, and the next question without some understanding of how the Cat 3126 engine fuelsystem is installed you are asking for big out lay of money. The 3126 engine is not very forgiving,nor is the heui injection system. Dave Atherton Retired Cat mechanic

As I think I understand it based on what I've read here and what the CAT tech told me, CAT uses a two filter system, Freightliner 'cheaped out' per the CAT tech, and only used one filter, a 2 micron with attached water separator.

I'm a pretty good wrench but know squat about diesels in general and this 3126 in specific. One of the few things I know is that they are sensitive to contaminated fuel. The reason I asked the question was that if the only filter is a 2 mic when CAT recommends a 10-30 AND a 2 then if it could be easily added it might make sense.

What I think I'm hearing from you and Brett is to leave well enough alone and just carry some spare filters and pre-fill them with clean diesel before changing and to NOT use ether if an intake heater is hooked up.

I think that would be a very good idea. First of all Nobody makes a 2 micron fuel filter asmany claim to have. Cat has that filter ties up with patents. What claim to be a fuel water filteron your motorhome is not a 2 micron filter. Going back to my last post different company has madechanges to your fuel system that are out of the box as per way the Cat 3126 heui system willoperate. Depending on your money status I agree leave well enough alone. If perhaps you shoulddecide to move forth and make into a OEM cat system I can assist you through the process. ReasonI did not jump and put chills up and down your back, been doing this for 42 years and kinda layedback and do not want to sound like a know it all. But asked will provide you with tech support.youcan do at a later time. Your Cat 3126 is a real good engine and should provide you many miles ofuse. Forget to ask how many miles do you have on the motorhome. Are you ever going to be aroundQuartzsite, Az. In the winter or the FMCA rally at Perry, Ga. In mid March. If you going to attend wecan meet up and I can put on my Cat ET computer and pull up all the history off ECM on engine and If any fault codes are present. Dave Atherton Retired Cat Mechanic

David, does the CAT 2 micron filter fit the Freightlinter base with water separator base like the WIX 33783 which says it's a 2 micron? I have no problem using the CAT filter.

We might actually make the Perry rally and would love to take you up on your offer. I like to 'know' things and am going to try very hard on the Discovery not to keep fixing things until they fail....something that has been a pretty much life long problem for me.

I live in North Alabama. While new to the Diesel pusher world, we also own a 77 GMC motor and have it 'nearly' finished. The GMC International group is also having their spring rally about the same time.

Pinkertonk, earlier we talked about filters along with Brett. I mentioned at that time they claimfuel/water is 2 micron this is a incorrect statement and I indicate that. I know times have havechanged, but Cat 2 micron filter is the only filter that can be backed up with papers. If you areplanning to install a 2 micron filter in the system the correct location is between the fuel transferpump on transfer pump pressure discharge or pressure side ( so cat filter is being pressurize offfuel transfer pump than discharge hose off cat filter will connect up to the engine head.) Notethe only filter that can be located from fuel tank and transfer pump is what you have installed nowleave that alone ( it stays ). Remember you have to tie into the steel line off pressure side of transferpump between pump and head. you will need to buy all correct fitting from cat along with the fuelfilter base and a 1R-0751 fuel filter. be real careful cannot have any air leaks or any dirt presentbecause bigger problems will happen. closing again the cat 2 micron filter and base have to beinstalled at the pressure side of fuel transfer pump and discharge from 2 micron filter will go to head.notice the steel line between transfer pump and head, you need to buy from the correct fitting to connect into this steel line and fuel transfer pump. Remember also the present filter that you havelocated on the suction side of the transfer pump will stay on the suction side.when finished youwill have a primary filter on the suction side of pump and the secondary located after the transfer pump. cannot be any air leaks or any dirt present to make engine run.Dave Atherton Retired Cat Mechanic